Jim
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 posted on 23/4/05 at 04:41 PM |
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Blade clutch
Just seam to have killed the clutch in my Indy. Starts slipping at about 7k. Last year when i changed it I think I probably got the standard honda
springs. Would I be able to get away with an oil change and new springs or should i just get the whole lot?
I would get Honda plates and the MT 99 springs from PDQ that everyone rates.
Such an arse, got car booked into Elvington on the 7 May and working nights all next week, should get time week after if it's not raining.
Bleeding cars, it's the caras third clutch in 3500 miles
Jim
Jim
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shortie
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| posted on 23/4/05 at 04:52 PM |
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Really depends on the condition of the plates but may be worth changing them just in case, nothing worse than doing a track day and then the clutch
giving up on you.
You could maybe get an EBC street racer clutch and the PDQ springs.
Rich.
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Hellfire
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| posted on 23/4/05 at 08:04 PM |
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If your budget will stretch to it Jim, go for the Barnett clutch and springs from PDQ. If I were you though, I'd try just the Barnett springs
first.
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Jon Ison
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| posted on 23/4/05 at 08:23 PM |
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If MK have any in there springs are fine too, don't know where they get em from but i did a seasons racing on a set with no slipping.
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Jim
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| posted on 23/4/05 at 10:36 PM |
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Had the barnett clutch plates last time. They have lasted under a year! Before track day last year at elvington I put whol enew clutch plates in,
plain and friction plates and springs. Including track day it must have done about 500 miles on this set up.
Will get springs and standard honda plates as this combo lasted for 2500 miles last time around
Will fuly synth oil hurt the kelvar clutch plates without overfilling
Might have to visit MK but short on time
Cheers
Jim
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Peteff
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| posted on 23/4/05 at 11:22 PM |
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I've never heard a good word for fully synthetic oil in bikes, most say it causes clutch slip.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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ChrisGamlin
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| posted on 25/4/05 at 09:42 AM |
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No offence Pete as this isnt aimed at you specifically, but a lot of the bad comments that seem to float around about fully synth oils is from what I
can see largely hearsay and rumour, there doesnt seem to be many facts to back up the theory that synthetic oils per-se cause clutch slip.
I think bike clutches in general are sensitive to oil simply because they are sitting in it, and so some synthetic oils possibly do cause problems,
but between myself and about 4 friends with BECs we must have done over 100 trackdays in 3 years plus probably 20k road miles, all using various
flavours of fully synth (mainly Castrol R4 or Redline) with no ill effects. None of us have had any abnormal clutch problems and one is still on his
original busa clutch that was in the engine when he bought it!
[Edited on 25/4/05 by ChrisGamlin]
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Jim
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| posted on 25/4/05 at 11:09 AM |
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New springs on order from PDQ. I have just found a EBC street racer clutch in the cupboard , are these any good or should i get honda ones?
Cheers
Jim
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ChrisGamlin
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| posted on 25/4/05 at 11:15 AM |
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Is that the kevlar EBC one? If so then its OK, I had one - its not as smooth take-up as the Honda but it seemed to grip / last OK (still use the
Barnett springs tho)
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Jim
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| posted on 25/4/05 at 11:24 AM |
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Cool, will use it. It is the EBC street racer Kevlar one. will give it a try. Just need some oil now. saved some money at last
cheers
Jim
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ChrisGamlin
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| posted on 25/4/05 at 11:53 AM |
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Cool. Give all the clutch plates a good soak in oil overnight before you fit them, just to make sure the friction material is fully impregnated and
you dont get a dry one stick when you install it.
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tks
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| posted on 25/4/05 at 01:22 PM |
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mhhh
maybe
it is a good idea to
Put near the clutch live, the Diff ratio / topspeed/wheel info.
because of the nature of a clutch...
its easy if you pass a certain limit several times it will blow away..
and if you don't they can las amazingly long...
also driveing habbits are important
and of course a good working clutch cable/oil system...
What are the sites to the shops??
I'm almost to my first testride with all original stuff in it soow have no idea
how long it will last..
TKS
The above comments are always meant to be from the above persons perspective.
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ChrisGamlin
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| posted on 25/4/05 at 02:13 PM |
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Sorry TKS, I dont really understand what you are asking 
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tks
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| posted on 25/4/05 at 02:31 PM |
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Sorry Chris
sometimes my mind is faster then my english dictionary,
i asked for the Site of PDQ (already found)
and i gave the suggestion to put near the clutch life value for example 500miles.
the diff ratio / topspeed.
Because it is important data to know how much you "ask" from your clutch...
the greater the topspeed, the more torque your clutch needs to deliver....
or turn it reverse a slow topseepd = high acceleration and that meens lighter take of / minor clutch torque needed...
TKS
p.s. does any one if there are VFR800 PDQ kits available?? on the site i cant see them....
The above comments are always meant to be from the above persons perspective.
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ChrisGamlin
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| posted on 25/4/05 at 03:52 PM |
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Is that correct though? Im not sure but if the engine can only produce X amount of torque, why would there be any more force on the clutch regardless
of gearing (or weight)? If there's no more torque being put through the clutch in a BEC than in the bike, the only variables I can see are that
with a heavier/higher geared car you need to slip the clutch more to pull away - causing more wear / slippage, and also because the car is heavier and
doesnt accelerate as quickly, the engine is around peak torque for longer therefore the clutch is under maximum load for longer (although the max
force isnt any different to on the bike)?
[Edited on 25/4/05 by ChrisGamlin]
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alister667
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| posted on 25/4/05 at 07:25 PM |
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Chris, I suspect the weight of the vehicle would significantly affect the wear of the clutch. Imagine you disconnected the propshaft, so there was
very little resistance to the torque of the engine, the shearing force on the clutch would be very low - because there is so little resistance to it
turning. A clutch would last a lifetime.
Now think of the other extreme, putting a blade engine into a loaded Ford Transit say! Almost all the torque from the engine would try to slip the
clutch because there is so much resistance from the weight of the vehicle.
Perhaps my physics is wonky - I've been known to be spectacularily wrong before!! Or maybe I've picked you up wrong! Apologies if that
is so.
On a bike, not only is it a lot lighter, but you'd have to be in the British Superbikes before a bike rider put's a superbike engine /
transmission through it's paces like it would get in a much lower geared BEC.
My no 1 tip on clutches is always leave a bit of loose play at the top of your clutch pedal so the clutch definitely is fully engaged - and always
drive with your left foot nowhere near the pedal.
All the best
Ali
http://members.lycos.co.uk/alister667/
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tks
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| posted on 25/4/05 at 07:50 PM |
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yeah,
i think the same as alister....
in fact...i know it sounds trange chris..
but the torque that delivers your bike engine offcourse is the maximum needed of the clutch springs, else it would slip in every gear..
but the hihger the topspeed the more resitance the air is giveing to the car, and that's the reason that i think it will slip faster than..
also think that at 9.000rpm and a bit of slip during 10seconds..and your plates of fiber are gone..
TKS
p.s. what about the honda springs??
in fact the problem is not slipping when you want it, its more slipping because of higher loads...
also don't forget that if you use cable clutch you need to have it loosen, because of the fact that new plates are thicker than old ones and
that results in the fact that the cable lever will move away from the padle (when they are wearing).
Imagine it is hanging in your cable and it slips..??
perhaps this is wy you only do 500miles with them did you measure the plates after time??
(On an hydro clutch, there is a spring in the slave cilinder, that one holds the pressure on the package, while wearing..)
[Edited on 25/4/05 by tks]
The above comments are always meant to be from the above persons perspective.
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ChrisGamlin
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| posted on 25/4/05 at 09:13 PM |
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Hi Ali
No probs, I think I might be at least half wrong
Thinking about it again, in the context of this thread what TKS said about the clutch needing to be slightly stronger for higher geared cars is
correct and I was wrong, but what triggered my thought process into what I said is because I dont think the clutch sees more torque, it just
sees torque for longer - I might be totally up the wrong creek here though so someone please pick the gaping holes in my thought process!
If you hold or even rev an unloaded engine at its peak torque rpm when its not loaded, it wouldnt be open throttle so wouldnt actually be producing
much power/torque, it only starts to do some work as you apply a resistance to the propshaft. Once the resistance is sufficient that you can give it
full open throttle then its only the time factor that changes, not the amount of torque on the clutch which surely cant change as it is driven
directly off the crank, producing
up to a maximum of x amount of torque (this isnt dependent on weight or gearing, just revs and throttle).
So, a very heavy / high geared car takes longer to get from 1000rpm - 10,000rpm at full throttle, hence the clutch has been put under load for a
certain amount of time longer than it would have been if the car was lighter and/or lower geared. I think you could assume that if a BEC took say 3
seconds to go from 4,000rpm to 10,000rpm in 2nd gear, and it took the bike the same amount to time to go through the same rev range in the same gear,
even though the bike would have accelerated quicker the load would have been the same on the clutch because the clutch would have been accelerated by
the same force from 4000rpm to 10,000rpm in the same timescale. If the bike gets through the gears quicker than a BEC (regardless of their relative
acceleration) then the clutch will have an easier time in the bike than the BEC, but if the BEC can get through the gears faster then under those
conditions (ignoring slipping the clutch to pull away etc) it would give the clutch an easier life than on the bike.
Probably if bikes were accelerated all the way to 150mph regularly (equivalent to our 100-110mph which we do quite regularly on track etc) then the
bikes would see the same clutch wear as we do.
I think
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alister667
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| posted on 25/4/05 at 11:55 PM |
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Hehehe quite a head mangler!!
I see where you're coming from Chris.
To be honest I can see your logic, but I'm now unsure!!!
Wish I'd paid more attention during physics!
http://members.lycos.co.uk/alister667/
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tks
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| posted on 26/4/05 at 07:12 AM |
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mh....
i agree an part with you story...
but you have to mention what you aks from the clutch,
you have to see it as 2sides thing...
low revs and high weight isn't an problem, because it cant wear fast at low revs...
but but but High load and high revs and moments of slip don't go together.........
also you have to know that the torque on the clutch is increasing if you use a higher gear... (see it on your mounting bike, the torque you need to
deliver when lowering the back sprockets [changing to smaller one] increases the stress on your muscles.. and that's in fact a high topspeed car
and imagine that an you go up an hill if then the clutch cant deliver the torque it slips and ones it slips..you are gone....
going up an hill is an extra tress becouse the resistance is then much much higher (hill climbing) in fact if you put it in neutral and lossen the
brakes the car rolls backwards...and that force is an extra resistance for the clutch....
the clutch is the weakest part of the system
depending on how my clutch now works (with an 3,92 diff i might try an 3,34 one
at least i have 9 plates in it... soow an strong clutch..!!
The above comments are always meant to be from the above persons perspective.
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ChrisGamlin
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| posted on 26/4/05 at 08:16 AM |
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This is all going rather off the original topic but I think we answered Jim's question so I hope he doesnt mind
TKS - the example you are using of a bicycle, when you are lower geared its the equivalent of the BEC accelerating with little load on it (in neutral
for example) as there isnt enough resistance to allow you to give your own personal peak torque, so effectively you are at part throttle. It is only
when you get high enough up the gears or you go up a steep hill where you can apply "full throttle" to your legs and produce your peak
torque, but the amount of torque your legs can produce is the same regardless, you dont suddenly gain super human powers when it comes to a
hill, its just that you weren't putting in full effort beforehand. In the BEC though we are assuming the engine can put in maximum effort at all
times (ie you can apply full throttle in all gears).
If we substitute the clutch in the BEC for the pedal crank on your bicycle, the maximum amount of torque that pedal crank ever sees is the maximum
amount of torque your legs can provide, if you do lots of up-hill riding it is more likely to break but only because its at high load for longer, but
the peak is still the same. If you come across a hill that is too steep to climb in the gear you are in, you can't suddenly generate extra
torque to compensate, you just slow down.
Put back in the bike engine scenario, run it on a dyno and hold the engine at peak torque with full throttle open, the engine is producing its peak
torque and the clutch is under the most amount of stress. Now wind the dyno up to put even more load on the engine - what happens - the engine doesnt
suddenly produce more torque to counter-act, it just slows down because its already giving out as much as it can, therefore the clutch never sees more
than the torque that can be applied by the engine.
I think it's because us BECs generally have the engines revving higher for longer periods than they would in the bike under normal conditions,
this is why we get more clutch wear.
All a bit of a brain basher tho
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tks
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| posted on 26/4/05 at 08:22 AM |
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ok,
now see it the other way,
if the dyno is putting 200N/M on the clutch
and the engine only 150N/M
will the lcutch then don't stand stil??
or go reverse direction??/
its difficult anyway..
TKS
The above comments are always meant to be from the above persons perspective.
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ChrisGamlin
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| posted on 26/4/05 at 08:52 AM |
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In that scenario the engine would just slow down, stall and then be forced to run backwards if you continued to apply the 200Nm, the clutch still
wouldnt see any more than 150Nm.
If you think about it, when you buy a competition gearbox or a clutch for a car, they are always rated by the amount of engine torque they can handle,
not by how heavy or high geared the car is they are being installed in.
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tks
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| posted on 26/4/05 at 11:21 AM |
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ok,
soow you think
your bec clutch will work with that engine in a ford transit..???
i don't, it will slip en not because the engine torque..
or how is that one/?
The above comments are always meant to be from the above persons perspective.
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ChrisGamlin
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| posted on 26/4/05 at 12:09 PM |
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If geared so it could pull away then yes it would "work" in the tranny .
Imagine the clutch basket had a 1m pole welded onto the side of it so you could use it as a lever and turn the clutch. You can put x amount of force
on that bar due to your strength, which lets assume for the sake of this that its the same amount of torque as the bike puts out, 70lbft. If the
engine is in a BEC, the car moves when you push/pull the lever because you have overcome the mass and accelerated it, if you then put the engine in
the transit it doesnt move because the car is too heavy or friction is too high, but the clutch has no more tendancy to slip because it still sees
your 70blft of torque you are applying, its just the force needed to move the transit is higher than you can apply. Now put the car on a steep hill
with it trying to roll backwards - you put your 70lbft torque on the bar, and the car either goes forward, it stays still, or it overcomes you and
still rolls backwards. In this scenario you were still only able to apply 70lbft to the clutch because thats all you can give, regardless of whether
the car accelerated, stayed still, or rolled backwards and pushed you away.
Its the same with the engine, it applies as much force as it can, and thats all the clutch ever sees unless in odd circumstances such as if you
dropped it off the jacks whilst the rear wheels were spinning, this sudden shock could produce more force because the momentum of the engine
components suddenly being stopped would probably add additional torque for a split second.
[Edited on 26/4/05 by ChrisGamlin]
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